1. Field of the Invention
The invention relates to management of communication networks, and in particular to a system for connecting multiple devices and transmitting high throughput data between the devices.
2. Related Art
Telecommunication systems continue to evolve and expand their presence in modern society. As an example, wireless networking has grown in popularity as a result of the improvements in portable computers (i.e., laptop computers), wireless technology, broadband access to the Internet, network gaming, and the growing popularity of networking computer systems together into local area networks (“LANs”) for both business and consumer applications. The most popular types of wireless networks for connecting multiple computers are at present configured utilizing the Institute of Electrical and Electronics Engineers (“IEEE”) 802.11 standard, which are generally known as a “802.11 networks,” “Wireless Fidelity networks,” “Wi-Fi networks,” or “WiFi networks.”
Generally, an 802.11 network includes at least two communication devices in signal communication with each other via a wireless signal path, where “in signal communication” generally means that the at least two communication devices may be electrically, optically, and/or magnetically connected, coupled, adjoined, affixed, attached, bonded, fastened, chained, harnessed, hooked, strapped, tied, clasped, mated, interfaced, fused, combined, or assembled in a way that allows either direct signals, information, data, or packets of data to pass from one communication device to another communication device via the signal path. An Access Point (“AP”) acts as a communication hub for the plurality of wireless communication devices to connect into a wireless LAN (“WLAN”) and/or into a wired LAN if the communication device is in signal communication with the wired LAN. The wireless communication devices are generally known as “802.11 clients,” “clients,” “client devices,” “stations” (“STAs”), “802.11 stations,” “nodes,” and/or “802.11 STAs.” Additionally, when STAs are in signal communication with an AP, it is referred to as infrastructure mode.
With the maturing of the different amendments of the baseline standard (such as, for example, IEEE 802.11a, 802.11b, and 802.11g) for 802.11 networks, there is an increasing interest in home networking to enable users to enjoy the ubiquitous availability of digital content that a home network provides. In these networks, many forms of data may be exchanged between the network devices including, for example, voice, financial and business information, digital content, audio and/or visual (“AV”) material, and e-mail, to name a few. Much of this information, such as AV material, generally requires that large amounts of data be transmitted across the network.
Unfortunately, existing 802.11-based WLANs were primarily designed and deployed with the functionality and intention of supporting data-centric applications, as opposed to media applications, where the traffic generated by these data-centric applications is typically presented to the network in bursts of large amounts (e.g. e-mail data and/or file transfer data). Generally, this traffic is not required to meet any targets for latency of delivery, nor is this traffic required to have a specific lower limit of bandwidth so as to provide a satisfactory user experience. As such, traffic generated by these data-centric applications is commonly referred to as “best-effort” traffic.
However, the next generation of WLAN devices are expected to carry data (i.e, “streams of data”) that originate from multimedia sources, and that have explicit and implicit requirements regarding both latency of delivery and minimum bandwidth. This new type of traffic is referred to as quality of service (“QOS”) traffic.
As a result, if the WLAN network components (and the WLAN itself) are unable to provide sufficient bandwidth to meet the QOS-specific bandwidth requirements and/or are unable to deliver QOS traffic within the QOS-specific latency requirements, then the user experience for the applications that generated the QOS traffic will be compromised, and potentially, unsatisfactory.
The next generation of WLAN technology includes some new functionality that is intended to provide adequate bandwidth and latency for QOS applications through additional, higher speed physical layer data rates and enhanced medium access control (“MAC”) features that allow differentiation of access to the network for packets from different classes of service, as well as providing efficiency enhancements. However, a difficulty in the deployment of new products that employ the next generation of WLAN technology for the delivery of multi-media streams is that the new products need to coexist with existing WLAN network technology.
As an example, a problem exists when a WLAN network is already installed in a home or office and a user wishes to add both a multi-media source and a multi-media sink to the WLAN network. Unfortunately, if two IEEE 802.11 clients attempt to exchange data between one another in infrastructure mode, data is exchanged through the AP where the data is first sent from the first client to the AP and then the AP retransmits the data to the second client because traditional WLAN networks rely on the AP as a layer-2 and sometimes layer-3, redirector of traffic. Traditionally, all traffic in the WLAN must pass through the AP, where the AP determines the next “hop” in the path to the destination and forwards the packet further along that path. For example, data that is sourced from one network STA and intended for delivery to another STA must pass through the AP, even though it may be physically possible for the two endpoints (i.e., the two STA) to communicate directly. This may cause data between clients to take approximately twice as long to be delivered or to utilize twice as much throughput.
As an example in FIG. 1, a block diagram of an example of an implementation of a known network architecture 100 for data transfer between client devices utilizing the 802.11 standard is shown. As mentioned above, in infrastructure networks, the 802.11 standard requires that data transfer occur between an AP and a client device. As an example, the known network architecture 100 may include Device A 102, Device B 104, and Device C 106. In this example, Device C 106 is in signal communication with both Device A 102 and Device B 104 via signal paths 108 and 110, respectively. Additionally, Device C 106 may function as an AP, and Device A 102 and Device B 104 may function as STAs where Device A 102 functions as a media server and Device B 104 functions as a media render. Generally, a media server is device, or software module, that processes multimedia applications such as, for example, AV streaming, still image storage, and music streaming programs. A media render is a device, or software module, that is capable of receiving and processing data from the media server and possibly also presenting that information to the end user.
In an example of operation, if Device A 102 is to transmit data to Device B 104, a data signal 112 is first transmitted from Device A 102 to Device C 106, via signal path 108, and then retransmitted from Device C 106 to Device B 104 via signal path 110. While this arrangement is functional, it is not efficient since it takes approximately twice as long to transmit data from Device A 102 to Device B 104 through Device C 106 than it would to directly transmit the data from Device A 102 to Device B 104. Unfortunately, this generally reduces the total throughput in a shared medium transmission system such as an 802.11 network by approximately one-half.
As an example, if a new multi-media source (“MMS”) and multi-media sink (“MMK”) are added to the known network architecture 100, they will communicate with the AP (such as, for example, Device C 106) as new clients. As a result, all traffic from the MMS (i.e., a new multi-media stream) must pass through the AP in order to eventually reach the MMK. In this example, it is appreciated that the path through the AP requires each packet of data for the multi-media stream to be transmitted twice—once by the MMS and once by the AP. Because the WLAN medium is shared among all transmitters of the WLAN, the total available network bandwidth is reduced by these second transmissions. For example, a stream of packets originating from a source that is connected non-wirelessly (such as on an Ethernet) to the AP will traverse the WLAN only once to reach a client STA of the AP. However, a stream of packets that is sourced by a STA of the AP must be sent twice on the WLAN in order to reach another STA of the AP. It is appreciated that if all transmissions in the network require a second wireless transmission by the AP, then the second transmission effectively reduces the total available bandwidth to one-half. Alternatively, any traffic which requires a second wireless transmission by the AP requires twice the bandwidth of a transmission which does not require a second wireless transmission by the AP.
Attempted solutions to this problem include an IEEE 802.11 e amendment to IEEE 802.11 that includes a Direct Link Setup (“DLS”) functionality that allows data transfer to be setup directly between clients. In FIG. 2, a block diagram of an example of an implementation of the traditional network architecture 200 utilizing the proposed IEEE 802.11e DLS functionality for data transfer between clients is shown. As an example, the known network architecture 200 may include Device A 202, Device B 204, and Device C 206. In this example similar to the previous example shown in FIG. 1, Device C 206 is in signal communication with both Device A 202 and Device B 204 via signal paths 208 and 210, respectively. However, unlike the example in FIG. 1, in this example, Device A 202 and Device B 204 may be in signal communication via signal path 212. Similar to FIG. 1, in this example, Device C 206 may function as an AP, and Device A 202 and Device B 204 may function as STAs where Device A 202 functions as a media server and Device B 204 functions as a media render.
In an example of operation, if Device A 202 is to transmit to Device B 204 utilizing IEEE 802.11e DLS (or similar proposals), Device A 202 negotiates with Device C 206 in order to setup a connection with Device B 204. Device C 206 then negotiates a connection with Device B 204 and after negotiation Device A 202 transmits data directly to Device B 204 without passing through Device C 206. Therefore, in this example, Device C 206, acting as an AP, must be utilized by both Device A 202 and Device B 204 in order to enable Device A 202 and Device B 204 to communicate to each other even if the communication is going to be only between Device A 202 and Device B 204.
While under certain circumstances the process of data transmission as described in FIG. 2. may be more efficient than the process described in FIG. 1, the process described in FIG. 2. unfortunately requires that all three communicating devices on the network implement the new DLS functionality. Generally, the DLS functionality needs the participation of the AP during the exchange of DLS setup frames including a set of setup frames called Traffic Specifications (TSPECs). AP participation is unlikely in a typical scenario because there are approximately 100 million 802.11 devices that had already been deployed in the field before the creation of the IEEE 802.11e amendment that defined DLS functionality. Additionally, the next generation IEEE 802.11e WLAN mechanisms to support QOS streams are presently considered complex and costly to implement and, as a result, most vendors have chosen not to support DLS functionality or some other features of 802.11e that are necessary for DLS functionality. As such, APs that have been created, purchased and/or deployed following the release of the IEEE 802.11e amendment are still unlikely to support DLS functionality. Therefore, there is a need for a system and method to transmit data between client devices with high overall throughput and low latency that is backward compatible with existing network devices.